Pulley block



Dec. 16, 1930. A. R CAMPBYELL 1,784,935

PULLEY BLOCK Filed May 9; 1925 TOR I I A/V/b A. .n qbe/b,

BY Fig. 5. 67M

ATTORNEY Patented Dec. 16, 1930 UNITED STATES ALVIN R, CAMPBELL, F SEATTLE, WASHINGTON PULLEY BLOCK Application filed May 9,

invention is notto be considered as limited toany such specific application, but is to be considered as extending to all fields where like conditions and problems obtain.

In logging, it is necessary to carry the tackle up steep'slopes into locations =very 1 difficult of access. Thus, it is customary-for the tackle to be carriedmanually "up steep slopes, over fallen timber andthrough underbrush, so that it is positively essential for efficient operation to have the pulley blocks constructed in a manner which will permit of their being assembled and'disassembled readily and without the carrying of special tools. The GXtGIlSlVG-SC21I6,UPOI1 which logging is now conducted, requires blocks of 25 large size, often weighing several hundred pounds. In logging, the block, which is thus most frequently transported and is of a size that it must be disassembled, is known as a corner block. Therefore, a primary ob- 80 ject of my invention is to provide a block which may be readily disassembled, the parts carried by separate individuals, and then capable of being readily reassembled at the point where it is desired to mount the block.

In thus providing such a block, it is desirable to have the side members in separate parts. As these side members are the mounting means for the pin, upon which the sheave is mounted, it will be manifest that these side members must be maintained in parallel position. The method of construction heretofore obtaining was such that when the block was disassembled once or twice, the fitting of the parts was lost, because the construction involved in the first instance a driving fit. That is, the pin, in particular, which constitutes the mounting shaft for the sheave, is ordinarily of straightwalled 0r cylindrical form, and the hole in the side members in which the ends of this mounting pin are 1925. Serial 116, 29,058.

located is ofsuchsizethat it is necessary'to drive thepin; through the same, and thenia nut is tightly secured-to the threaded endof the pin. Thus, the driving in and use of this pin very quickly reduces the nicety of fitting, 5 the loss of which immediately results in a play which very quickly develops a decided misalignment of-the sheave, andsincethese I pulley'blocks are often called upon to stand stresses of from forty to fifty tons, such misalignment readily results in. breaking the block or rendering it unfit for further use. A-primary object of-my invention is to provide a block of such constructionthat it-may be disassembled and atthe same timethe I proper degree ofrnicety of fitting of the parts i shall not be lost by such disassembling and reassembling. Aifurther primary object of my invention is to provide a block of the character described, which will also be characterized by a great reduction in its weight, owing to the disposition and form of the parts constituting my invention.

The above mentioned general objects of my invention, together with others inherent in the same, are attained by the device illustrated in the following drawings, the same being merely a preferred exemplary form of embodiment of my invention, throughout which drawings like referencenumeralsin-; 88 dicate like parts: V

Figurel is a view, inside 'elevationofa pulley block embodying my invention;

Fig; 2 is a view in end elevation and partly in section of the same; 7

Fig. 3 is an enlarged view of one end portion of the mounting pin and associated side member I I I 3 Fig. 4 islanienlargedview in section on dotted line 4, 4 of Fig and Fig; 5 is a-view in cross section on line 5, 5 of Fig. 3. v a I v The shell of the block is made in two pieces or side mounting members6 which, when as sembled, are held together at the top by the shackle .7 and pins18. The pins-8, have a slot-likeop'ening 24 adapted to operate as a wrench fora set screw 23. Also,-said pins are preferably provided with ;a-Isqua-re-cor- V nered :head25, so; thatpin vfizmaylbc used; as

a drift in removing keys 11. These pins 8 are secured in place by the cotter pins 9. The two parts of the shell are further held together by the pin 10, having tapered end portions 26 and the tapered keys 11. I prefer to make the pin 10 with tapered ends and ream the holes in the shell or side members with taper to correspond, so thatwhen the keys 11 are driven through the slotted holes 12 in the pin, the keys bearing on the tapered seat 13 at the bottom of the keyway'll in the shell or side member 6 secure a rigid connection of the shell to the pin 10. The shell is also provided with recesses 22 above. the keyways 14 into which the pins 8 are inserted for drifting. out keys 11.

The keys 11 are secured against accidental backing or dropping out by the set screws 28, which are secured down firmly afterthe keys 11 are driven home. The keys 11 are provided with a longitudinal groove 15, shown in section in Fig. 5. The points of the set screws 23 enter this groove. The

groove 15 terminates near the smaller end of the key, so that when the set screws are loosened suflicientto allow the keys 11 to drop clear of the pin 10, they are still preand locked with cotter pins 20 which pass through holes 21 in the pin 10.

The block is taken down in the following manner: One of the pins 8 is-removed, releasing the two sides 6 of the shell at the top. The set screws 23 are backed half a turn only with a wrench, which is provided by the opening 24 in the pin 8, and the pin 8 is furtherused as a drift, the square head 25 being ap lied against keys 11 to start them out. nce started, they are easily pulled out as faras the point of the set screws 23 will permit. 7 A light blow with a hammer, first on one end, then on the other,

i of the pin 10 releases the two parts of the shell 6 owing to the tapered end portion 26. The blockis now in three parts, the pin 10 with the sheave on it, and the two parts of the shell, one having the shackle 7 attached. A distinct advantage is thus obtained in having the pin 10 and the sheave mounted together, so that they are not readily taken apart. Otherwise, if they are taken apart,

.to fit the key way slot in said sheave pin and said slot in said side members; and a releasably mounted shackle operatively disposed to unite the tops of said side members.

2. In a pulley block, a sheave mounting.

pin, said pin having a key slot therethrough, shell side mounting members operatively disposed upon said sheave pin, said mounting members having a tapered key slot therein, and a tapered key disposed in said lastnamed key slot and through said key slot in said sheave pin, whereby said pulley block may be readily assembled and disassembled.

8. In a pulley block, a sheave mounting pin having tapered end portions; two shell side mounting members having tapered bearings which register with said tapered end portions; a tapered pin means which holds said shell mounting members on said pin; and means mounted injsaid shell members which. engage said tapered pin when partially disengaged, whereby said pin is kept in assembled position with said shell members. v

In witness whereof, I hereunto subscribe my name this 30day of April, 1925. ALVIN R. CAMPBELL.

serious objection obtains in that experience proves that the pin and the bearings are dropped in the dirt and become fouled, with the result that they quickly burn out when put into operation. The reassembling of the block is obviously areversal of theoperations just described. 7

Obviously, changes may be made in the 

